Heretofore, a variety of devices have been used to monitor wear in audio cartridges such as the standard NAB cartridges commonly used in commercial radio broadcast studios. Such cartridges are typically used as program/message sources, and may be replayed numerous times, such as in the case of a popular song or commercial. If the cartridge/tape has worn such that the quality of reproduction has significantly decreased, the listener or advertiser may well be dissatisfied, to the ultimate economic detriment of the station. It is, therefore, important to detect the onset of such unsatisfactory performance, which may often precede the point at which even trained operators in a control room can audibly detect problems. Furthermore, in many instances, such trained ears may not be listening, particularly as stations rely more and more on automated operations.
Typical wear monitors used in the past have relied on some form of sensing the mechanical performance of the cartridge. Thus, for example, strain-gauge-like sensors have been spring loaded against the tape surface. The output, indicated on a meter or dial may then be monitored to detect undue variations in or excessive levels of tape tension. Similarly, tape tension has been monitored by measuring the relative current in the tape drive motor, for if the tape pack tension varies, the drive current required to maintain constant tape speed will also vary. It is also known to detect absolute cartridge failures, such as from jammed cartridges or broken tapes, etc., and to provide automatic switch-over signals, alarms, and the like.
While such techniques have been somewhat useful, they have generally been limited to either laboratory or maintenance environments where specially trained personnel and equipment may be present. No such techniques have been suggested for real-time, on-the-air broadcast studio use by relatively non-technically trained personnel.